Buggy code:
public class ConfigurationFactExtractor { private static final int DEFAULT_CISCO_VLAN_OSPF_COST = 1 ; private static final String FLOW_SINK_INTERFACE_PREFIX = "TenGigabitEthernet100//" ; private static String getLBRoutingProtocol ( RoutingProtocol prot ) { } private Set < Long > _allCommunities ; private Configuration _configuration ; private Map < String , StringBuilder > _factBins ; private List < String > _warnings ; public ConfigurationFactExtractor ( Configuration c , Set < Long > allCommunities , Map < String , StringBuilder > factBins ) { } public List < String > getWarnings ( ) { } private void writeAsPaths ( ) { } private void writeBgpGeneratedRoutes ( ) { } private void writeBgpNeighborGeneratedRoutes ( ) { } private void writeBgpNeighborPolicies ( ) { } private void writeBgpNeighbors ( ) { } private void writeCommunityLists ( ) { } public void writeFacts ( ) { } private void writeGeneratedRoutes ( ) { } private void writeInterfaces ( ) { } private void writeIpAccessLists ( ) { } private void writeLinkLoadLimits ( ) { } private void writeOriginationPolicies ( ) { } private void writeOspfGeneratedRoutes ( ) { } private void writeOspfInterfaces ( ) { } private void writeOspfOutboundPolicyMaps ( ) { } private void writeOspfRouterId ( ) { } private void writePolicyMaps ( ) { StringBuilder wSetPolicyMapClauseAddCommunity = _factBins . get ( "SetPolicyMapClauseAddCommunity" ) ; StringBuilder wSetPolicyMapClauseDeleteCommunity = _factBins . get ( "SetPolicyMapClauseDeleteCommunity" ) ; StringBuilder wSetPolicyMapClauseDeny = _factBins . get ( "SetPolicyMapClauseDeny" ) ; StringBuilder wSetPolicyMapClauseMatchAsPath = _factBins . get ( "SetPolicyMapClauseMatchAsPath" ) ; StringBuilder wSetPolicyMapClauseMatchAcl = _factBins . get ( "SetPolicyMapClauseMatchAcl" ) ; StringBuilder wSetPolicyMapClauseMatchCommunityList = _factBins . get ( "SetPolicyMapClauseMatchCommunityList" ) ; StringBuilder wSetPolicyMapClauseMatchNeighbor = _factBins . get ( "SetPolicyMapClauseMatchNeighbor" ) ; StringBuilder wSetPolicyMapClauseMatchProtocol = _factBins . get ( "SetPolicyMapClauseMatchProtocol" ) ; StringBuilder wSetPolicyMapClauseMatchRouteFilter = _factBins . get ( "SetPolicyMapClauseMatchRouteFilter" ) ; StringBuilder wSetPolicyMapClausePermit = _factBins . get ( "SetPolicyMapClausePermit" ) ; StringBuilder wSetPolicyMapClauseSetCommunity = _factBins . get ( "SetPolicyMapClauseSetCommunity" ) ; StringBuilder wSetPolicyMapClauseSetLocalPreference = _factBins . get ( "SetPolicyMapClauseSetLocalPreference" ) ; StringBuilder wSetPolicyMapClauseSetMetric = _factBins . get ( "SetPolicyMapClauseSetMetric" ) ; StringBuilder wSetPolicyMapClauseMatchTag = _factBins . get ( "SetPolicyMapClauseMatchTag" ) ; StringBuilder wSetPolicyMapClauseSetNextHopIp = _factBins . get ( "SetPolicyMapClauseSetNextHopIp" ) ; StringBuilder wSetPolicyMapClauseSetOriginType = _factBins . get ( "SetPolicyMapClauseSetOriginType" ) ; String hostname = _configuration . getHostname ( ) ; for ( PolicyMap map : _configuration . getPolicyMaps ( ) . values ( ) ) { String mapName = ( hostname + ":" ) + ( map . getMapName ( ) ) ; List < PolicyMapClause > clauses = map . getClauses ( ) ; for ( int i = 0 ; i < ( clauses . size ( ) ) ; i ++ ) { PolicyMapClause clause = clauses . get ( i ) ; switch ( clause . getAction ( ) ) { case DENY : wSetPolicyMapClauseDeny . append ( ( ( ( mapName + "|" ) + i ) + "\n" ) ) ; break ; case PERMIT : wSetPolicyMapClausePermit . append ( ( ( ( mapName + "|" ) + i ) + "\n" ) ) ; break ; default : throw new BatfishException ( "invalid<seq2seq4repair_space>action" ) ; } for ( PolicyMapMatchLine matchLine : clause . getMatchLines ( ) ) { switch ( matchLine . getType ( ) ) { case AS_PATH_ACCESS_LIST : PolicyMapMatchAsPathAccessListLine matchAsPathLine = ( ( PolicyMapMatchAsPathAccessListLine ) ( matchLine ) ) ; for ( AsPathAccessList asPath : matchAsPathLine . getLists ( ) ) { <START_BUG> String asPathName = asPath . getName ( ) ; <END_BUG> wSetPolicyMapClauseMatchAsPath . append ( ( ( ( ( ( mapName + "|" ) + i ) + "|" ) + asPathName ) + "\n" ) ) ; } break ; case COMMUNITY_LIST : PolicyMapMatchCommunityListLine mclLine = ( ( PolicyMapMatchCommunityListLine ) ( matchLine ) ) ; for ( CommunityList cList : mclLine . getLists ( ) ) { String cListName = ( hostname + ":" ) + ( cList . getName ( ) ) ; wSetPolicyMapClauseMatchCommunityList . append ( ( ( ( ( ( mapName + "|" ) + i ) + "|" ) + cListName ) + "\n" ) ) ; } break ; case IP_ACCESS_LIST : PolicyMapMatchIpAccessListLine mialLine = ( ( PolicyMapMatchIpAccessListLine ) ( matchLine ) ) ; for ( IpAccessList list : mialLine . getLists ( ) ) { String listName = ( hostname + ":" ) + ( list . getName ( ) ) ; wSetPolicyMapClauseMatchAcl . append ( ( ( ( ( ( mapName + "|" ) + i ) + "|" ) + listName ) + "\n" ) ) ; } break ; case NEIGHBOR : PolicyMapMatchNeighborLine pmmnl = ( ( PolicyMapMatchNeighborLine ) ( matchLine ) ) ; long neighborIp = pmmnl . getNeighborIp ( ) . asLong ( ) ; wSetPolicyMapClauseMatchNeighbor . append ( ( ( ( ( ( mapName + "|" ) + i ) + "|" ) + neighborIp ) + "\n" ) ) ; break ; case PROTOCOL : PolicyMapMatchProtocolLine pmmpl = ( ( PolicyMapMatchProtocolLine ) ( matchLine ) ) ; RoutingProtocol prot = pmmpl . getProtocol ( ) ; wSetPolicyMapClauseMatchProtocol . append ( ( ( ( ( ( mapName + "|" ) + i ) + "|" ) + ( ConfigurationFactExtractor . getLBRoutingProtocol ( prot ) ) ) + "\n" ) ) ; break ; case ROUTE_FILTER_LIST : PolicyMapMatchRouteFilterListLine mrfLine = ( ( PolicyMapMatchRouteFilterListLine ) ( matchLine ) ) ; for ( RouteFilterList rfList : mrfLine . getLists ( ) ) { String rflName = ( hostname + ":" ) + ( rfList . getName ( ) ) ; wSetPolicyMapClauseMatchRouteFilter . append ( ( ( ( ( ( mapName + "|" ) + i ) + "|" ) + rflName ) + "\n" ) ) ; } break ; case TAG : PolicyMapMatchTagLine pmmtl = ( ( PolicyMapMatchTagLine ) ( matchLine ) ) ;

Fix:
String asPathName = ( hostname + ":" ) + ( asPath . getName ( ) ) ;